Railway signaling system



May 3 1927.

E. C. LARRY RAILWAY SIGNALING SYSTEM Filed Dec.14, 1925 Patented May 3, 1927.

UNITED STATES PATENT OFFICE.

EDWIN C. LARRY, OF ROCHESTER, NEW YORK, ASSIGNOB TO GENERAL RAILW AY SIGNAL COMPANY, OF RGCHWTER, NEW YORK.

RAILNAY SIGNALING SYSTEMi Application filed December 14, 1925.

This invention relates to automatic block signaling systems, and more particularly to means tor checking the failure o'f'a block signal to give a danger or stop indication when the block at the entrance of which it is located, is occupied.

luone type of block signal system, to which the present invention more particularly relates, polarized track or line cir cuits are used to govern the indications of semaphore signa s, the polarity of said track or line circuits being reversed by polechangers mechanically operated by the signals. If, tor any reason, a smtaphore signal should stick in its clear position and fail to assume its stop position when it; should. thepole-changer operated by that signal fails to reverse the" polarity of the circuit for the signal next in the rear, with the result that tlie signal in the rear indicates clear when it should indicate caution.

In accordance with the present invention, it is proposed to cause the next signal in the rear of a signal in question to remain in the stop position if the signal in question is out of order and is giving a false proceed indication, that is, if it'fails to go to stop when it should. More specifically it is proposed to provide a stick relay at each signal location in connection with a circuit arrangement whereby the next signal in the rear of such signal location will indicate stop, or danger, when the stick relay at the signal location mentioned is (ls-energized, and to provide means for energizing such stick relay which is closed only after thesignal'adjacent thereto assumes the stop position. In other words, the stick relay mentioned is deenergized each time a train passes and if the signal does not assume the danger position in response to such passage of the train, the stick relay will not be again picked up and the signal next in the rear is caused to indicate danger.

Other objects, purposes, and characteris tic features of the invention will readily ap pear as the description thereof progresses.

In describing the invention in detail, reference will be made to thesingle drawing which shows one track of a double track railroad in which the normal direction of traffic is from left to right, as indicated by the arrow, and inwhich the trackrails 1 are divided into blocks by insulating joint-s Serial No. 75,337.

2. of which the-block l and the adjacent ends of two other blocksH and J only, have been shown. Since the various circuits and devices at each signal location are the same; like parts of each block are designated by like reference characters having distinctive exponents. The block I has bridged across the entrance end thereof an alternating current track relay T, and the exit end of this block is provided with the usual trackway source of energy, which in the particular embodiment of the invention illustrated comprises a transformer 4 Since the present invention is more particularly applicable to semaphore signals, there has been pro vided at the entrance to each block, a semaphore signal Z which normally assumes its clear indicating position by reason of energization of the clear wire 5, such signal assuming the caution position if the caution wire (3 only is energized, and assumes the danger position if neither of these two wires are energized; these signals including the usual electrically operated mechanism, which for convenience has been omitted from the drawings, the power for operatingthe signals being derived from a suitable local source of energy such as a battery having its terminal B connected to the contact 7 of the track relay and having its other terminal connected to a common return wire C. These semaphore signals Z also have a contact blade 8 associated therewith, which assumes a position corresponding to that of the signal blade, and are further provided with snap pole changer contacts 9 and 10, which change quickly from their normal to their abnormal dotted position as the semaphore signal blade moves from either the clear or caution to the danger position.

Each of the blocks is provided with a stick relay SR, which is normally energized through two partial circuits which, for the, relay SR may be traced as tollmvsz-(l) beginning at the terminal B of a sui able source of energy, contact l2 oi the track relay T wires 13 and l-l. st c: contact 15 of the relay SR. wires 16 and 17'. winding of the relay SR to the common return wire C connected to the other side of saidsource of energy. and (2) beginning at the terminal B of a suitable source of energy, contact 18, wires 19, 20, and 14 stick contact 15, wires 16 and 17 winding of the relay SR to the loo common return wire (3 connected to the other side of said source of energy. It should be noted that the track transformer 4 supplies track circuit current to the block I through contacts 22 and 23 of the relay SR, so that the block I is deprived of track circuit current if the stick relay SR is de-energized; also, it should be noted that the polarity of the track circuit current of the block I is reversed whenever the signal at the entrance to the block J is at danger by reason of the pole changer contacts 9 and 10 operated by the signal Z, and that such reversal of the track circuit current of block I causes the track relay T to assume the reverse position and causes the signal Z to assume the caution position.

In order to understand the embodiment of the invention illustrated clearly, it is considered expedient to first consider the movement of a train in the normal direc tion of tratfic, when the signals are in working order, and to then assume the passage of a train when the signal Z fails to go to danger upon the passage of the train by the signal. Let us assume that a train is moving from left to right in the block II and that it enters the black I. The entrance of the train upon the track circuit of block I causes the track relay T to assume its deenergized position by reason of shunting action of the wheels of the train, thus causing the signal Z to assume its danger position because there is no current applied to either the clear wire 5 or the caution wire 6. Also, the dropping of track relay T causes the contact 18 to assume its pendent position, but this does not de-energize the stick relay SR because this stick relay is held up through the contact 12 Also, movement of the contact 12 to its pendent position causes the stick relay SE to assume its (lo-energized position, because the contact 18 (not shown) of the track relay at the entrance to the block II is also in its pendent position and open, this on the assumption that the rear end of the train is still in the block H. Immediately after the train has entered the block I, the signal Z assumes its danger position and causes a pickup circuit for the stick relay SR to be completed, which may be traced as follows: Beginning at the terminal P) of a suitable source of energy, semaphore contact 8, wires 27 and IT, winding of the stick relay SR to common return wire (l connected to the. other terminal of said source of energy. This causes the stick rclay SR to pick up and soon as the 'rear end of the train leaves the block H. its stick circuit is again completed through the wire 20. As the train passes the signal Z, the same signal, relay and circuit c :angcs take place at the signal Z as just described in connection with the signal Z, so that no further discussion of the operation under proper working of the signals is deemed necessary.

Let us now assume that a train is moving from left to right through the block Hand that it enters the block I, and causes the contact 18 to assume its pendent position for reasons heretofore given. Let us further assume that the train continues its movement and moves into the block J, that it causes de-cnergization of the stick relay SR. Let us further assume that the signal Z is out of order and fails to assume the danger position. The failure of the semaphore of signal Z to move to its danger position also causesfailure of the pickup circuit for the stick relay SR to be completed, so that,

this stick relay SR remains in its de-energized position, and permanently cuts off track circuit energy off of the block I, So as to cause the track relay T to remain deenergized thereafter. \Vith the track relay permanently dc-energized, the signal Z will of course assume the danger position, and in so doing will cause the pole changer contacts 9 and 10 to assume the dotted position and in turn cause the signal at the entrance of the block H to assume the caution position. In other words, since the signal Z failed to go to danger, the signals at the entrance to the blocks I and II assume the danger and caution position, respectively, in spite of favorable traffic conditions ahead.

In studying the circuit arrangements illustrating the present invention, it would at first appear that the contact 18 and the line wire 20 are entirely unnecessary. If, however, its contact 18 and line wire 20 were omitted, the sudden change of a signal by reason of the opening of a switch at a siding in a block, the backing of a train from a block in advance into the block in ques tion. or the like, would cause signals to tumble down, so to speak, one after another, in the rear of such block; this being true because the sudden dropping of a track re lay would cause its corresponding stick relay to drop, which in turn would cut off energy of the next block in the rear. thereby causing its track relay and stick relay to drop, etc., ad intinitum. With the provision of the contact 18 and line wire 2t), however, the stick relay SR will not drop even though the track relay '1 drops due to the backing of a train into the block J, the opening of a switch in the block .I. or the like. In other words this undesirable tumble down is avoided by the provision of line wire 20 and contacts 18.

Having thus shown and described a single embodiment of the invention which not only causes a signal in the rear of a signal out of order to go to danger, and" the next signal in the rear thereof to a to caution, but which is so organized that no-undesirable and unwarranted signal indications are given, due to the backing ofa train into a block orthe sudden change of abloclr from clear to danger for other reasons, such as the opening of aswitch insuch block; and having described the selected embodiment rather specifically, it is desired to be understood th'at th-is has not been done to illustrate the exact construction preferably 'employed in practice, nor thescope of-the invention, and that variousclrangesand modifications may be made'toadaptthe' invention-to the particular local conditions encountered in practicingthe'invention; for instance, a direct current sourcemay be used instead of alternating current for track circuit purposes andi polar neutral relays may be used instead' of t'h-rce position relays,- allwithout departing from the sco e of the invention or the idea-of means for carrying'out the same.

Vhat I claim as new is 1. In ablock signalingsystem, the combination witlratrack divided into blocks by insulating' -jo-ints each blockinclndinga t'raclr relay andasource' of energy connected to form the usualclosed track circuit, a semaphore signal at the entrance to each block, and means effective if a particular semaphore signal does not assume the danger position upon the passage of a train by such signal for causing the next semaphore signal in the rear to assume its danger position.

2. In a block signaling system the combination with a track divided into blocks by insulating joints each block including a track relay and a source of energy connected to form the usual closed track circuit, a semaphore signal at the entrance to each block, and means for causing the next semaphore signal in the rear of a particular semaphore signal to assume its stop position if that particular signal does not assume the danger position while the block at the entrance to which it is located is occupied.

3. In a block signaling system the combination with a track divided into blocks by insulating joints each block including a track relay and a source of energy connected to form the usual closed track circuit, a semaphore signal at the entrance to each block, a stick relay associated with each of said semaphore signals, means for de energizing said stick relay upon the passage of a train by its associated semaphore signal. and means for picking up said stick relay if such semaphore signal assumes its danger position upon the passage of a train thereby.

4. In a block signaling system, the combination with a track divided into blocks by insulating joints each block having the usua litraclc circuit including a track relay and a tracltway' source'of energy, a signal at'the'eiitrance' to each block, a-stick relay associated with" each signal and having a pickup circuit'nnda stick circuit, said pickup circuit including contacts operated by said signal and closed if it is in its stop position, said sticlr circuit including contacts closed it the traelc relay adjacent theassoci'a-ted signal is energized 5; In a block signaling'system, the combination with a track divided into blocks by insulating joints each block having the usual track circuit including a'tra'clr-relay and a trackwaysource' of energy, a signal at the entrance to each bloclr, astick relay havingfa piclr-u-pcircuit: and a stic r circuit associated with each of said signals, said pick -u=p-- circuit including' contacts closed only if the associated signal assumes the danger position, and said stick circuitco1nprising two partial circuits" in innltiple one of which includescontacts closed' when the track relay adjacent the associated signal is energized and the other of which includes contacts closed when the next track relay in the rear is energized.

6a In-a bloclr signaling system, the comhinationwitha t'rack divided into blocks by insulating joints eachblock?'ha vii-ig the usual track circuit including a track relay and a trackway source of energy, a signal at the entrance to each block, a stick relay associated with each of said signals and having a pick-up circuit and a stick circuit, said pick-up circuit including contacts closed only if the associated signal assumes the danger condition, said stick circuit comprising two partial circuits in multiple one of which includes contacts closed When the track relay adjacent the associated signal is energized and the other of which includes contacts closed when the next track relay in the rear is energized, and means for causing said next signal in the rear to assume the danger condition when said stick relay is de-energized.

7. In a block signal system for railroads having blocks equipped with polarized track circuits, a semaphore signal for each block, a pole-changer operated by each signal, a source of current and electrical connections between each pole changer and the track rails of the block next in the rear for supplying track circuit current, and means associated with each track relay and its corresponding signal for breaking said electrical connections to cut oil track circuit current from the block in the rear whenever said track relay is de-energized and said corresponding signal is not in its stop position.

8. A block signal system for railroads having polarized track circuits comprising in combination, a polarized track relay for each block, a semaphore signal for each block, a

pole-changer operated by each signal, a source of track circuit current, electrical connections between said source and pole-changer for reversing the polarity of the track circuit current for the block nextin the rear, and means for interrupting the supply of current from said source to its track circuit in the rear Whenever the track relays of a given block and the next block in the rear are deenergized and the signal at the entrance to said given block does not assume its stop position. I

9. In a block signal system of the character described including polarized track circuits, the combination with a track relay for each block, of means responsive to the presence of a train in a given block and governed by the track relay of the block next in advance for cutting off the supply of track circuit current to the track circuit of said given block. 7

10. In a block signal system for railroads having tracks divided into blocks each provided with a track circuit, a semaphore signal at the entrance to each block, a polechanger operated by each signal, means for governing each signalfby the track circuit of its block and by the pole-changer operated by the signal next in advance, and automatic means for causing each signal to indicate stop independently of the occupancy of its block if the next block in advance is occupied and the signal of said next block in advance is not in its stop position.

11. In a block signal system having tracks divided into blocks each provided with a track circuit, a semaphore signal at the entrance to each block, a source of current and circuit connections including a pole-changer operated by each signal for governing the indications of the signal next in the rear, and means for breaking said circuit connec tions associated With a given signal if the block for that signal is occupied and that signal is not in its stop position.

12. In a block signal system having tracks divided into blocks each provided with a track circuit, a semaphore signal at the entrance to each block, a source of current and circuit connections including a pole-changer operated by each signal for governing the indications of the signal next in the rear, and means for'automatically breaking said circuit connections associated With a given signal if its block and the next block in the rear are simultaneously occupied and for maintaining said break until said given signal assumes its stop position.

In testimony whereof I aflix my signature.

,EDWIN C. LARRY. 

